Answers

Subtract 72/81 from 90/30

1^st number: 3 0/30, 2^nd number: 72/81

90/30 - 72/81 is 19/9.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 30 and 81 is 810
   
   Next, find the equivalent fraction of both fractional numbers with denominator 810
2. For the 1st fraction, since 30 × 27 = 810,
   90/30 = 90 × 27/30 × 27 = 2430/810
3. Likewise, for the 2nd fraction, since 81 × 10 = 810,
   72/81 = 72 × 10/81 × 10 = 720/810
4. Subtract the two like fractions:
   2430/810 - 720/810 = 2430 - 720/810 = 1710/810
5. After reducing the fraction, the answer is 19/9
6. In mixed form: 21/9

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